This application seeks funding for a Total imaging matrix (Tim) upgrade for the Siemens 3T Trio whole-body MRI system operated by the UC Davis Imaging Research Center (IRC). The IRC is university-wide center that provides state-of-the-art MRI for all human, and some non human primate, research projects at UC Davis. The Siemens 3T Trio MRI system has enabled the neuroimaging community at UC Davis to thrive. The IRC now has 35 active neuroimaging investigators, equally distributed across the School of Medicine and the Colleges of Letters and Science, and Biological Sciences, and it provides imaging support for over $60 million in extramural grants. Sixteen major NIH funded research projects (e.g. P01, R01) are supported by the MRI system and are described in this proposal. The Tim upgrade is necessary for the IRC to continue to provide state-of-the-art imaging capabilities to its users. This upgrade will result in the IRC having the most advanced MRI hardware and software platform available. The software platform is that on which Siemens develops its MRI technical advances, and is the platform on which many multi-site neuroimaging clinical trials are conducted. The upgrade will improve the quality of all structural and functional images. The new data acquisition hardware is expected to provide 25% improvement in signal-to-noise ratio (SNR) for structural imaging, and 20-60% improvement in temporal stability for functional MRI (fMRI). New advanced sequences for faster high resolution 3D structural imaging with T1, T2, and proton density contrast, and sequences for diffusion tensor imaging (DTI) that produce less geometric distortion, are provided in the upgrade software. Finally, the upgrade provides much quieter scanning, up to 90% less sound pressure, critical to fMRI studies in healthy children and adults, and patients. Investigators in UC Davis'Center for Neuroscience, MIND Institute, Center for Mind and Brain, Alzheimer's Disease Center, and related departments, utilize imaging to address a wide range of research questions using fMRI, structural MRI and DTI. Imaging research includes basic neuroscience and translational studies of perception, cognition and motor function, and includes the investigation of major disorders such as Alzheimer's Disease, and developmental disorders such as autism, Fragile X, FXTAS pre-mutation disorder, and attention deficit disorder. Leading neuroanatomists at UC Davis are also using high resolution MRI and DTI to reveal the structure of the developing and adult macaque monkey brain in collaboration with the California National Primate Research Center located at UC Davis, with the goal of establishing high-quality image databases for future investigations at UC Davis and internationally. All these research programs depend on high spatial resolution MRI to reveal brain structure, and rapid single-shot MRI acquisition techniques to reveal brain function. Finally, UC Davis investigators are both leading and participating in multi-site research studies that require the use of advanced imaging sequences across multiple MRI platforms and imaging centers. PUBLIC HEALTH RELEVANCE: Researchers at the University of California Davis are internationally recognized leaders in research designed to answer a wide range of questions in neuroscience, neurology, psychiatry, and the behavioral sciences. In their research, Magnetic Resonance Imaging (MRI) plays a major role by allowing them to measure many aspects of brain structure and function, in patients with developmental, neurological and psychiatric disorders as well as normal individuals. This grant application will support a significant upgrade of the MRI system at UC Davis that is currently used by these researchers, providing them significantly greater capabilities to evaluate brain structure and function, and accelerate the progress made towards understanding the normal human brain and treating and preventing brain disorders.